Urea hydrolysis reaction mixing device
By optimizing the structural design of the urea hydrolysis reaction mixing device, the problem of uniformity between exhaust gas and urea solution was solved, achieving efficient reduction of nitrogen oxides and reducing deposition, thus meeting stringent emission standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI SHENZHOU CATALSIS PURIFIER CO LTD
- Filing Date
- 2025-07-15
- Publication Date
- 2026-06-02
AI Technical Summary
The poor uniformity of tail gas and urea solution in the existing urea hydrolysis reaction mixing device leads to uneven local reaction, which may cause urea solution deposition and affect long-term operation.
The design incorporates a tangential swirl inlet structure, a gradient porous reaction plate, honeycomb microchannels, baffle channels, and spiral blades to optimize gas-liquid mixing and reaction processes. Through multi-stage airflow guidance and catalytic pyrolysis-hydrolysis reactions, it achieves uniform decomposition and efficient mixing of urea solution.
It improves nitrogen oxide reduction efficiency, meets stricter emission standards, reduces nitrogen oxide emissions, prevents urea solution deposition, and extends equipment life.
Smart Images
Figure CN224315058U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automotive engine exhaust purification technology, specifically to a urea hydrolysis reaction mixing device. Background Technology
[0002] A urea hydrolysis reaction mixing device is used to generate ammonia through hydrolysis of urea as a reducing agent. The ammonia then reacts with nitrogen oxides in flue gas during selective catalytic reduction (SCR), reducing them to harmless nitrogen and water, thereby reducing nitrogen oxide emissions from the flue gas. In addition to flue gas denitrification, this device can also be used to treat nitrogen oxides in other industrial waste gases. By optimizing the atomization, mixing, and reaction processes of the urea solution, the efficiency of ammonia generation and nitrogen oxide reduction is improved. The urea hydrolysis reaction mixing device is a key component in flue gas denitrification systems and is of great significance for reducing air pollution and protecting the environment.
[0003] In existing urea hydrolysis reaction mixing devices, urea solution is fed into a urea dissolving tank via a bucket elevator or pump. Under the action of a catalyst, the urea solution is heated to a certain temperature and pressure to carry out a hydrolysis reaction, which decomposes urea into ammonia and carbon dioxide. However, in traditional devices, when it is necessary to achieve uniformity between the tail gas and the urea solution, local uneven concentrations are easily caused, resulting in insufficient reaction in some areas and excessive reaction in others. This may lead to the deposition of urea solution in the device, which is a technical problem that affects long-term operation. Utility Model Content
[0004] The purpose of this invention is to provide a urea hydrolysis reaction mixing device to solve the technical problem that in the prior art, when the tail gas and urea solution are mixed evenly in a conventional device, local uneven concentration is easily caused, resulting in insufficient reaction in some areas and excessive reaction in other areas, which may lead to urea solution deposition in the device and affect long-term operation.
[0005] The technical problem to be solved by this utility model can be achieved through the following technical solution:
[0006] A urea hydrolysis reaction mixing device, including a housing;
[0007] The outer shell is connected to an exhaust gas inlet pipe at one end. The exhaust gas inlet pipe is a tangential swirl inlet structure. A mixing pipe is connected to the exhaust gas inlet pipe. A mixing gas outlet pipe is connected to the end of the outer shell away from the exhaust gas inlet pipe. A catalyst inlet pipe is connected to the mixing gas outlet pipe. A reaction chamber is connected inside the outer shell. A locking mechanism is connected between the reaction chamber and the outer shell.
[0008] A reaction plate is fixedly connected inside the reaction chamber, and multiple honeycomb microchannels are provided on the reaction plate; a mixing chamber is fixedly connected inside the reaction chamber, and a flow guide hole is opened on the mixing chamber. A baffle channel is provided inside the mixing chamber, and multiple primary flow guide plates are connected to the mixing chamber.
[0009] The outer shell is connected to the bottom of the reaction chamber by a urea input pipe, and a urea nozzle is provided on the side wall of the outer shell.
[0010] As a further embodiment of this utility model: the locking mechanism includes a bolt, and two connecting plates are fixedly connected to the reaction chamber, with the bolt being detachably connected between the two connecting plates.
[0011] As a further embodiment of this utility model: the two connecting plates are arc-shaped plates.
[0012] As a further aspect of this invention, the reaction plate adopts a gradient porous structure.
[0013] As a further embodiment of this utility model: the honeycomb microchannel is a cordierite honeycomb ceramic carrier.
[0014] As a further aspect of this invention, the honeycomb microchannels are coated with a catalyst.
[0015] As a further embodiment of this utility model, the flow deflector channel is a three-dimensional spiral deflector structure.
[0016] As a further aspect of this invention, a spiral blade is provided inside the reaction chamber.
[0017] As a further embodiment of this invention, the urea nozzle is an air-assisted atomizing nozzle.
[0018] As a further embodiment of this utility model: the outer shell is connected to the bottom of the mixing chamber by a compressed air pipe and a condensate drain pipe.
[0019] The beneficial effects of this utility model are:
[0020] 1. In this invention, high-temperature exhaust gas from the engine enters through the exhaust gas inlet pipe and undergoes initial diffusion through the mixing pipe. Multiple primary guide vanes divide the exhaust gas into multiple turbulent streams, extending the airflow path. Urea solution is introduced and delivered to the urea nozzle through the urea inlet pipe. Compressed air pipe provides auxiliary atomizing airflow, further refining the droplets. The urea droplets contact the high-temperature exhaust gas within the honeycomb microchannels. The airflow refracts within the mixing chamber, extending the residence time. The gradient design of the guide hole aperture controls the flow rate and avoids excessively high local ammonia concentrations. By optimizing the mixing and reaction process, nitrogen oxide emissions in the exhaust gas can be reduced more effectively, meeting stricter emission standards and improving mixing and reaction efficiency.
[0021] 2. The spiral blades of this invention generate a secondary swirling flow, ensuring uniform distribution of NH3. The NH3-containing mixed gas enters the catalyst inlet pipe through the mixed gas output pipe and is transported to the SCR catalyst. The condensate drain pipe automatically discharges unreacted urea solution when the system is shut down. The arc-shaped connecting plate and bolts form a quick-release structure. The high-speed airflow from the guide hole washes the wall surface, reducing crystal deposition. The NH3-containing mixed gas is transported to the catalyst inlet pipe through the mixed gas output pipe, which helps the catalyst to reduce nitrogen oxides more effectively. The condensate drain pipe automatically discharges unreacted urea solution when the system is shut down, which helps prevent the accumulation of unreacted urea in the system. Attached Figure Description
[0022] The present invention will be further described below with reference to the accompanying drawings.
[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0024] Figure 2 This is an exploded structural diagram of the present invention;
[0025] Figure 3 This is a schematic diagram of a partial structure of the reaction chamber in this utility model;
[0026] Figure 4 yes Figure 3 Diagram of the back structure;
[0027] Figure 5 This is a schematic diagram of the mixing chamber structure in this utility model.
[0028] In the diagram: 1. Outer shell; 2. Mixed gas output pipe; 3. Catalyst inlet pipe; 4. Reaction plate; 5. Reaction chamber; 6. Connecting plate; 7. Mixing chamber; 8. Bolt; 9. Honeycomb microchannel; 10. Primary guide plate; 11. Guide hole; 12. Baffle channel; 13. Exhaust gas input pipe; 14. Urea input pipe; 15. Urea nozzle; 17. Mixing pipe; 18. Compressed air pipe; 20. Condensate drain pipe. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0030] like Figures 1-5As shown, a urea hydrolysis reaction mixing device includes a shell 1, with a tail gas inlet pipe 13 connected to one end of the shell 1. The tail gas inlet pipe 13 has a tangential swirl inlet structure, and a mixing pipe 17 is connected to the tail gas inlet pipe 13. A mixed gas outlet pipe 2 is connected to the end of the shell 1 away from the tail gas inlet pipe 13, and a catalyst inlet pipe 3 is connected to the mixed gas outlet pipe 2. A reaction chamber 5 is connected inside the shell 1, and a locking mechanism is connected between the reaction chamber 5 and the shell 1. The locking mechanism includes bolts 8. Two connecting plates 6 are fixedly connected to the reaction chamber 5. The two connecting plates 6 are arc-shaped plates, and the bolts 8 are detachably connected between the two connecting plates 6. The tangential swirl inlet structure generates swirling turbulence when the tail gas enters, enhancing the mixing uniformity with the urea solution and avoiding local concentration unevenness. The mixing pipe 17, in conjunction with the swirl inlet, further optimizes the airflow distribution and improves the reaction efficiency.
[0031] A reaction plate 4 is fixedly connected inside the reaction chamber 5. The reaction plate 4 is provided with multiple honeycomb microchannels 9. The reaction plate 4 adopts a gradient porous structure. The honeycomb microchannels 9 are cordierite honeycomb ceramic carriers. The honeycomb microchannels 9 are coated with catalyst. The porous structure of the reaction plate 4: the pore size gradually decreases along the airflow direction, so that the gas distribution is more uniform and the catalytic efficiency is improved. The cordierite honeycomb ceramic carrier: has high thermal stability and low thermal expansion coefficient, and is suitable for high-temperature exhaust gas environment.
[0032] A mixing chamber 7 is fixedly connected inside the reaction chamber 5. The mixing chamber 7 has a flow guide hole 11 and a baffle channel 12. The baffle channel 12 is a three-dimensional spiral baffle structure. Multiple primary guide vanes 10 are connected to the mixing chamber 7. Spiral blades are provided inside the reaction chamber 5. The three-dimensional spiral baffle structure causes the airflow to form a spiral flow, prolonging the residence time and enhancing the mixing effect of urea droplets and exhaust gas. The primary guide vanes 10 optimize the airflow direction, reduce the flow dead zone, and improve the reaction uniformity. The spiral blades further promote gas-liquid mixing and improve mass transfer efficiency.
[0033] The outer shell 1 is connected to the bottom of the reaction chamber 5 by a urea input pipe 14. A urea nozzle 15 is provided on the side wall of the outer shell 1. The urea nozzle 15 is an air-assisted atomizing nozzle. The outer shell 1 is connected to the bottom of the mixing chamber 7 by a compressed air pipe 18 and a condensate drain pipe 20. The air-assisted atomizing nozzle 15 atomizes the urea solution into fine droplets, which improves the evaporation and reaction rate and reduces the risk of deposition.
[0034] The working principle of this utility model is as follows: The device achieves efficient decomposition of urea solution into ammonia gas and uniform mixing with exhaust gas through multi-stage airflow guidance, catalytic pyrolysis-hydrolysis reaction and dynamic mixing optimization. The high-temperature exhaust gas from the engine enters from the exhaust gas inlet pipe 13 and is initially diffused through the mixing pipe 17. Multiple primary guide vanes 10 divide the exhaust gas into multiple turbulent streams, extending the airflow path. The urea solution is input and delivered to the urea nozzle 15 through the urea inlet pipe 14. The compressed air pipe 18 provides auxiliary atomizing airflow to further refine the droplets. The urea droplets and the high-temperature exhaust gas come into contact in the honeycomb microchannel 9. The airflow is folded back in the mixing chamber 7 to extend the residence time. The guide hole 11 has a gradient design to control the flow rate and avoid excessively high local ammonia concentration.
[0035] The spiral blades generate a secondary swirling flow, which makes the NH3 distribution uniform. The NH3-containing mixed gas enters the catalyst inlet pipe 3 through the mixed gas output pipe 2 and is transported to the SCR catalyst. The condensate drain pipe 20 automatically discharges unreacted urea solution when the machine is stopped. The arc-shaped connecting plate 6 and the bolt 8 form a quick-release structure. The high-speed airflow of the guide hole 11 washes the wall surface and reduces crystal deposition.
[0036] The above description details one embodiment of the present utility model, but it is merely a preferred embodiment and should not be construed as limiting the scope of the present utility model. All equivalent variations and improvements made within the scope of the present utility model application should still fall within the patent coverage of the present utility model.
Claims
1. A urea hydrolysis reaction mixing device, comprising a shell (1); characterized in that: The outer shell (1) is connected to an exhaust gas inlet pipe (13) at one end. The exhaust gas inlet pipe (13) is a tangential swirl inlet structure. A mixing pipe (17) is connected to the exhaust gas inlet pipe (13). A mixed gas outlet pipe (2) is connected to one end of the outer shell (1) away from the exhaust gas inlet pipe (13). A catalyst inlet pipe (3) is connected to the mixed gas outlet pipe (2). A reaction chamber (5) is connected inside the outer shell (1). A locking mechanism is connected between the reaction chamber (5) and the outer shell (1). A reaction plate (4) is fixedly connected inside the reaction chamber (5), and multiple honeycomb microchannels (9) are provided on the reaction plate (4); a mixing chamber (7) is fixedly connected inside the reaction chamber (5), and a flow guide hole (11) is opened on the mixing chamber (7). A baffle channel (12) is provided inside the mixing chamber (7), and multiple primary flow guide plates (10) are connected to the mixing chamber (7); The outer shell (1) is connected to the bottom of the reaction chamber (5) by a urea input pipe (14), and a urea nozzle (15) is provided on the side wall of the outer shell (1).
2. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The locking mechanism includes a bolt (8), and two connecting plates (6) are fixedly connected to the reaction chamber (5). The bolt (8) is detachably connected between the two connecting plates (6).
3. The urea hydrolysis reaction mixing device according to claim 2, characterized in that, The two connecting plates (6) are arc-shaped plates.
4. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The reaction plate (4) adopts a gradient porous structure.
5. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The cellular microchannel (9) is a cordierite cellular ceramic carrier.
6. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The honeycomb microchannels (9) are coated with a catalyst.
7. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The deflection channel (12) is a three-dimensional spiral deflection plate structure.
8. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The reaction chamber (5) is equipped with spiral blades.
9. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The urea nozzle (15) is an air-assisted atomizing nozzle.
10. The urea hydrolysis reaction mixing device according to claim 1, characterized in that, The outer shell (1) and the bottom of the mixing chamber (7) are connected to a compressed air pipe (18) and a condensate drain pipe (20).